Do vaccines cause autism? Here’s what experts say

The McCullough Foundation’s report reviews over 300 studies linking vaccines, genetics, and environmental factors to autism. (Image: Pexels)

A study shared by Zoho founder Sridhar Vembu has revived the discredited claim that vaccines cause autism. Uploaded to Zenodo, an open-access digital repository where anyone can post research, the paper was co-authored by Dr. Peter McCullough and Dr. Andrew Wakefield, both linked to the anti-vaccine movement. Health authorities have dismissed the claim as false and lacking scientific basis.

The World Health Organization, the Indian Academy of Paediatrics and US Centers for Disease Control and Prevention (CDC) have also refuted such claims and maintained that vaccines are safe and that extensive research worldwide has found no causal link between vaccination and autism.

Vaccine skepticism resurfaces amid political noise and outbreaks

The report, published on Zenodo and not hosted in any peer-reviewed journal, comes amid renewed vaccine scepticism in the US, fuelled by high-profile figures such as US President Donald Trump and US Health Secretary Robert F. Kennedy Jr., both known for questioning immunisation programmes.

In September 2025, Trump claimed that both prenatal use of paracetamol (Tylenol) and early childhood vaccines may be contributing to rising autism rates. He urged pregnant women to “avoid Tylenol” and hinted at revising vaccination schedules for children. The claims came after US President Donald Trump and Health Secretary Robert F. Kennedy Jr. commissioned a report exploring potential causes of the rise in autism diagnoses, including vaccines and prenatal use of acetaminophen.

Also Read: No clear evidence to establish paracetamol-autism link: Dolo maker Dilip Surana counters Trump’s claim

The Trump administration has been under immense pressure from Health Secretary Robert F. Kennedy Jr.'s diverse Make America Healthy Again movement to provide answers on the causes of the marked increase in autism cases in the US in recent years.

Following these remarks, the US FDA announced it would review acetaminophen warning labels — though experts clarified there is no scientific evidence supporting a causal link between either factor and autism.

Echoing similar sentiments in India, Zoho founder Sridhar Vembu recently wrote on X, “Parents should take this analysis seriously. I believe there is increasing evidence that we are giving way too many vaccines to very young children. This is spreading in India too, and we are seeing a rapid increase in autism.”

Parents should take this analysis seriously. I believe there is increasing evidence that we are giving way too many vaccines to very young children. This is spreading in India too and we are seeing a rapid increase in autism in India. https://t.co/AeiVaieYug

— Sridhar Vembu (@svembu) October 28, 2025

A long-debunked controversy

The vaccine–autism debate dates back over two decades to a now-discredited 1998 paper by British gastroenterologist Andrew Wakefield that falsely linked the MMR (measles, mumps, rubella) vaccine to autism. The study was retracted by The Lancet for ethical and scientific misconduct, and Wakefield lost his medical license.

Despite overwhelming scientific evidence to the contrary, the myth continues to resurface — often amplified by social media and public figures.

What the McCullough report claims

Authored by McCullough and Wakefield, the new paper claims to be the most comprehensive review ever conducted on the topic, analysing over 300 studies. It concludes that vaccination is the “dominant preventable risk factor” for autism diagnosed before the age of nine.

🚨BREAKING — The Most Comprehensive Analysis Ever Conducted on the Causes of Autism Finds Vaccination Is the DOMINANT Risk Factor

After decades of censorship and denial, the McCullough Foundation’s Landmark Report of over 300 studies finally delivers the verdict:

Autism’s rise… https://t.co/VmQjx4CKoq pic.twitter.com/EePJpa1bxy

— Nicolas Hulscher, MPH (@NicHulscher) October 27, 2025

Scientists have criticised it for relying on selective citation and including discredited sources, including Wakefield’s earlier work.

WHO and medical experts dismiss the claims

The World Health Organization (WHO) has firmly rejected the report’s conclusions.

At a press briefing in Geneva, WHO spokesperson Tarik Jašarević said, “Vaccines save countless lives. Science has proven that vaccines do not cause autism, and these things should not really be questioned.”

He added that speculation around paracetamol use during pregnancy is based on “inconsistent data” and should not distract from the proven benefits of vaccination programmes worldwide.

In India, doctors echoed similar views. Dr Radhika Narula, a Mumbai-based gynaecologist, told Moneycontrol that autism spectrum disorder (ASD) “cannot be traced to a single cause.”

“It’s a complex condition shaped by both hereditary and environmental factors. Studies show that family history, certain gene variations, and prenatal complications can increase risk — but vaccines are not among them,” she said.

Dr Madhukar Bhardwaj, Director and Head of Neurology at Akash Healthcare, told Moneycontrol, “There is no credible scientific evidence associating childhood vaccines with autism or any other neurodevelopmental disorder. The fear stems from one fraudulent, since-withdrawn study. Numerous large-scale studies involving millions of children across countries have consistently shown that vaccines do not cause autism.”

Also Read: Autism causes and controversies: What science really says about vaccines, painkillers, and genetics

The scientific consensus

Experts agree that autism is a multifactorial neurodevelopmental condition shaped by genetic, biological, and early environmental influences — not vaccination. Misleading claims, they warn, risk undermining confidence in immunisation and could trigger a resurgence of preventable diseases such as measles and polio.

As Dr Bhardwaj summed it up, “Vaccines protect children from life-threatening illnesses. The real priority should be awareness, early diagnosis, and better support for children with autism — not fear of vaccines.”